a. Technical Field
The present invention relates to a protective circuit board for a battery pack, and more particularly to a protective circuit board for a battery which minimizes the influence of external electromagnetic waves and static electricity.
b. Description of Related Art
In general, a protective circuit board for a battery pack controls charge and discharge states of the battery pack and interrupts the current of the battery pack when it is overcharged or over-discharged to protect the battery pack and the user.
The structure of a protective circuit board will now be described briefly with reference to FIG. 1.
As shown, a conventional protective circuit board includes an insulation layer 10, at least one conductive first signal pattern 20 formed on a surface of the insulation layer 10 or on the opposite surface, at least one second signal pattern 30 formed on a surface of the insulation layer 10 or on the opposite surface, at least one conductive via 40 for electrically connecting the first and second signal patterns 20 and 30 to each other, and various electronic components 50, such as semiconductor ICs, switches, and/or LEDs, mounted on the first or second signal pattern 20 or 30.
Battery packs having a protective circuit board mounted thereon are frequently exposed to extreme conditions. For example, they are usually used at a place where severe electromagnetic waves occur or are exposed to naturally generated static electricity. Such electromagnetic waves or static electricity generally affect various electronic components on the protective circuit board. Particularly, noise or static electricity may act on the electronic components along first or second signal patterns formed on the surface of the protective circuit board.
The larger the length or area of the first or second signal patterns are, the more likely it is that electromagnetic waves or static electricity will flow towards the electronic components along the first or second signal patterns. As a result, conventional battery packs frequently malfunction as various electronic components fail to operate correctly under the influence of electromagnetic waves or static electricity.
In an attempt to minimize the influence of electromagnetic waves or static electricity, a case, which encloses the protective circuit board, may be subjected to secondary shielding treatment. Alternatively, silicone glue or tape may be attached thereto. However, such measures raise the overall manufacturing cost of battery packs and increase the weight.